Internationally, little consensus exists about the best treatment for cervical adenocarcinoma in situ (AIS). This study aimed to determine the incidence of recurrent high-grade cervical dysplasia and development of local cervical cancer after treatment for AIS. This nationwide, retrospective cohort study included patients with AIS, who were treated by a large loop excision of the transformation zone (LLETZ), cold-knife conization (CKC), or hysterectomy between January 1, 1990 and December 31, 2021 in the Netherlands. Pathology reports were retrieved from the Dutch Nationwide Pathology Databank (Palga). Primary outcomes were the cumulative incidences of high-grade cervical dysplasia (cervical intraepithelial neoplasia grade 2 or 3, and AIS) and local cervical cancer up to 20 years after primary treatment. In total, 4243 patients with AIS were included. The primary treatment was a LLETZ, CKC, or hysterectomy in 1593, 2118, and 532 patients, respectively. The incidence of recurrent high-grade cervical dysplasia after LLETZ (10.5%; 95%CI: 8.6-12.3) was higher than after CKC (5.5%; 95%CI: 4.4-6.6, p <.0001). When a radical excision, that is, surgical margins free of dysplasia at end of treatment, was achieved, the incidence of recurrent high-grade dysplasia and local cervical cancer did not differ between LLETZ (5.6% [95%CI: 3.3-7.9] and 1.9% [95%CI: 0-4.4]) and CKC (4.7% [95%CI: 3.5-5.8], p = .631 and 1.5% [95%CI: 0.7-2.3], p = .918). After hysterectomy, none of the patients developed cervical dysplasia or local cervical cancer. Conservative treatment for AIS can be considered a safe and final treatment modality when a radical excision is achieved.